I have a 98ls1.

#1. I put an slp lid and throttle body spacer. first was the throttle body spacer, let my ecu reset and it ran like a dream. put the slp lid on and the ecu has had time to reset but it feels a lot slower then before. esp when I punch it at 30 like im sure everyone in the automatics do for that downshift. Any help configuring these new item or help with a good program to tune it with etc? im assuming its just running lean.

#2 I got a cut out and had it installed right behind my y pipe. come to find out the put a 2' 3/4 on instead of a 3 inch. (this has been awhile) didn't notice a drop in power, sounds amazing, but how much am I robing myself? and should I go with a bigger one with new headers? Id hate to rip it out, put a 3 inch in then want a 3 1/4 in a yr with bigger headers.

#3. everyonetalks about subframe connectors but offers no suggestions. My car really needs some but I cant figure out which ones to go with. the straight bar ones or the more fancy multi point ones. weld or bolt?

Thanks for any and al suggestions

 

My 01 SS will only downshift into 3rd at 30 mph. My cut off for downshifting into 2nd is 27 mph and I'm the original owner and car is 100% stock. Maybe our speedos are not 100% calibrated right.

 

That was just a rough est. on the speed its usually a little below 30 but ive also noticed if I try and cruise at a constant speed it will cut in and out power quickly and often like the car is lost in the sauce about how much fuel air its getting. I think this weekend ill try closing the cutout and resetting the ECU to stock by disconnecting the batteries then let it reprogram from there since the cat is behind the cutout and might not be reading everything right?

 

If the cutout is in front of the cat your rear O2 is reading wrong and changing your fuel trims.

The proper location for your cut out is on the I pipe just before the bend to go up over the rear axle.

 

The after-cat O2 sensors' primary function is to make sure the cat is there and working properly. It has very little (if any) effect on fuel trims.... that's why it's easy to program them out or install O2 "sims". On the other hand, if the cutout is on collector headers, near the pre-cat sensors, there could be a backwash of air at low loads, really screwing up the LTFT's. That doesn't sound like your setup though.

A throttle body spacer serves no purpose on a dry intake manifold, with a huge plenum behind the throttle body. Waste of $$$$.

If you have a loss of power after installing the SLP lid, is it possible you don't have the MAF sensor properly sealed to the air box, and (more importantly) to the throttle body? Any air bypassing the MAF sensor will make it feel "flat" when you punch the throttle. Did you reconnect things like the IAT sensor?

What are your question regarding SFC's that no one can answer? Directionaly, you'll get more stiffening of the chassis with the X-brace style. Question is, do you need it? If you are into heavy auto-X/road racing, the added stiffness may be of some benefit. Otherwise, the SFC's that simply connect the front SF to the rear SF are more than adequate. I'm running straight tube SFC's on a t-top chassis with an 800HP/800 lb-ft nitrous motor, and no evidence of any chassis distortion. I do have a 6-pt roll bar, so that helps too.

I prefer welded to bolt-on, on the basis that I have seen evidence of the bolt-on connectors starting to tear the sheet metal in the subframes, and loosening up. But others don't seem to feel that's a big problem.

 

The car has over 160k on it and has been beat pretty good. Thanks for the advice ill prolly go with the straight ones for SFCs.

As far as the SLP lid goes I hooked everything back up and everythings tight except the lid itself in the back has a little play. I don't hear any air getting through and cant see anywhere it would. does anyone else with the SLP lid have wiggle room in the back?

With the cut out I got two conflicting replys. does anyone have anythings more then just hear say?